The prior art distillation apparatus is described in the following U.S. Patent Documents:
______________________________________ U.S. Pat. No. Date Inventor ______________________________________ 845929 3/5/07 Broonoippolito 2999796 2/9/59 Bromley 3136707 6/9/64 Hickman 3293153 12/20/66 Lustenader 3505175 4/7/70 Zalles 3536591 10/27/70 Lotz 3697383 10/10/72 Weaver 3837491 9/24/74 Humiston 3505175 6/17/86 Kusakawa et al. 4731159 3/15/88 Porter et al. ______________________________________
The prior art describes various types of stationary and rotary distillation devices. One type of prior art (e.g., Porter) requires heating (usually by steam) to partially vaporize a liquid. One drawback with this prior art apparatus is that a relatively large amount of energy is required to convert liquid to vapor. Another type of prior art (e.g., Bromley) is multi-effect in that some of the energy given off in condensation is used to vaporize additional liquid. The drawback with this type of multi-effect apparatus is that there is a pressure drop with each effect so that there is a limit to the number of effects. Another type of prior art as described by Hickman is a rotary distillation apparatus which transfers energy from the condensing to the evaporating surfaces by means of a compressor to condense vapor "at a sufficiently high temperature above that at which it is evolved". This apparatus requires an expenditure of energy to operate the compressor.